Method of distilling refined, cracked oils without avoidable decomposition or discoloration



- METHOD or'ms'rrnnmei Janrmm), CRACKED OILS WITHOUT- Avornaiannnncomrosr- No Drawing.

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unites FRANK G. .AXTELL, OF SOUTH PASADENA, CALIEOQRNIA, ASSIGNOIL 'IOAXTELLIQ} SEARCH LABORATORIES, INC., 013 LOS ANGELES, CALIFORNIA, ACOREORATION CALIFORNIA TION OR DISCOLORA'IION My present inventionrelates to the production of refined hydrocarbbnproducts such asgasoline derived from -so-calle'd cracked distillates.

It is known to those skilled in the art that When cracked petroleumdistillates are refinedforpurified by the ordinary method of treatmentwith more or less highly con- .Qcentratedsulphuric' acid (or With otheracid or mixture deri ed from sulphuric acid) such sulphuric acid orderivative thereof reacts with certain constituents of such crackeddistillates to formcompounds (as dialkyl sulphates) which, inthemselves, are of a perfectly neutral and stable character at ordinarytemperatures; and'that, when such refined distillate, isdistilled,bythe'time the temperature reaches about 350 F. to 370 F.

the compounds referred to are or may be decomposed,vvith liberation ofsulphuric and sulphurous acids. One or both of these acids thereuponreact with .the oil contained in the distilling apparatus, /with theresult that such oils are often badly polymerized, oxidizedand/orcarbonized,--the distillate becoming yellow and the oil contained in thestill becoming black and being rendered commercially almost or entirelyWorthless; and it is n a primary object of my invention to provide meansand methods whereby cracked oil, undergoing distillation, is stabilizedagainst the action of the sulphur acids liberated by the decom ositionof the bodies referred to.

I have. discovered that when a refined (acidtreated and neutralized)cracked distillate, containing the unstable compounds referred to isdistilled in the presence of a suitable stabilizing agent (an agentwhich has or which yields a substance having a greater affinity forithesulphur acids liberated by the decomposition than have the hydrocarbonoils for such acids) I am able to continue the distillation, through andbeyond that range Application filed February a, 1927. Serial No.166,817.

of gasolines and similar light products, as obtained fromcrackeddistillates.

It is known that cracked distillates contain relatively large quantitiesof unsaturated bodies; and that these bodies are not only ,55

of high fuel value but capable of contributng, aswhen present in aproportion amounting to about 6% or more to highly advantageousanti-knock effects; but the conservation of the mentioned unsaturatedbodies has or arating gasoline fractions therefrom, the hightemperatures which are necessary to the'distillation have incidentallyresulted .in the mentioned very undesirable polymerizing and discoloringeffects; and it is accordingly means and methods for the conservation ofthe mentioned unsaturates.

While I commit myself to no specific theory as to the advantageouseffects which I obtain by distilling in the presence of a suitable stablizing agent, it is my inference that the agel t referred to, byneutralizing the sulphuric acid radicle as fast as formed, ob-

viatc s an'attack by said sulphuric acid radicle upon unsaturates andother hydrocarbons,

and thereby prevents those polymerizing and carbonizing actions by whichthe still base is, in the absence of such stabilizing agent, likely tobe deleteriously afi'ected.

As implied'above, an essential feature 0 my present invention is theexecution of a distillation of cracked distillates in the presence of astabilizing agentyielding a basic radicle,s o that the distillation canbe-car-' ried to a desired end point Without. those polymerizing andcarbonizing effects which have heretofore commonly appeared a'ftert;-

the condensation of about 70% of the ob-X tainable yield, heating abovethis point in, the absence of a stabilizing agent having heretofore beenfound to ruin both the distillate and the still base, apparentlybyreason of the liberation of sulphuric acid under temi an object of mypresent invention to provide izing and/or carbonizing action, if it is'not.

promptly neutralized, asfast as formed.

Other objects of my invention, which per: mit of the use of a veryinexpensive stabilizing agentsuchas soda ash, andWhich permits of theuse of steam for a distillation effect, may be best appreciated from-thefollowing illustration of a specific embodiment thereof.

Adding to each barrel of a suitably refined, cracked distillate, aboutfive or six pounds of sodium carbonate or potassium carbonate (as, sodaash in solution or in suspension or in a dry and finely subdividedstate), I find that although the sodium carbonate or'- itsequivalent,'when dry, at first floats in a uniform andv well-distributedmanner throughout the oilfl-as the same reaches a temperature of about300 F. to 370 F., without the oil undergoing deterioration in color,the'carbonate' becomes viscous or creamy 1n consistency, at about 370F.; and that, 1n undergoing I either fire or steam distillation, arefined,

of a distillation executed in the indicated manner, to add a proportionof a suitably refined hyrocarbon distillate, such as kerosene, toacracked distillate, to produce a still base and, for an enhancement ofthe yield of gasoline, and to retain high boiling impurities and thatsodium hydroxide .andp0- tassium hydroxide are not so suitable as thesodium or potassium salts of volatile and non oxidizing acids (thealkali salts of aliphatic acids, such as acetic acid, beingobjectionable only by reason of their cost) sodium and potassiumhydroxide being themselves liable to produce polymerizing anddiscoloring effects. It will, also be understood that the. salts. ofcertain of the volatile and non-oxidizing acids, such as hydrochloricacid, are undesirable' for the same reason, and for this. reason,

I prefer to limit my stabilizin agents to alkali salts of volatilenon-oxi izing nonpolymerizing acids. It might be mentioned at thispoint, that, although carbonicvacid is not ordinarily thought of as. avolatile acid, it may inrelation to the present process be consideredas'such, in that when a carbonate is decomposed as, for instance, bysulphuric acid, the ultimate products of decomposition are a sulphate,carbonic enhydride and water, which are volatile and I may mention inconclusion, 'thatfalthough this describe I use of analkalior'decomposable salt in the fractionatin of cracked distillates isentire ly suitable for use i -processes such as are set forth-in mycopending application, Serial No. 157 ,427 filed December 27th, 1926,(disclosing a method'of using benzol andi ici its homologues inconection with sulphuric acid and in a manner immaterial to my presentinvention) the method herein described and claimed is entirely suitablefor use in the production .of high grade gasolines, of superiorqualityand maximum yield, from cracked distillates which have been treated withordinary sulphuric acid and subsequently neutralized in any ordinary orpreferred manner,with the added result that the residual still baseisobtained in the form of a stable, light-colored oil of commercialvalue,

instead of as a highly polymerized, partially carbonized, acid andpractically valueless product, I v

Although I have herein described a Single complete embodiment of myinvention, it should be understood. not only that various detailsthereof mightbe independently used, but also that numerousmodifications, additional to those suggested herein, might, be devisedby workers skilled in the arts to which this case relates, Withoutinvolving the slightest departure from the spirit and scope of mynvention as the same is indicated-above and in the following claims.

I claim as my invention:

1'. In the production of light hydrocarbon oils from crackeddistillates, the method of bbtaining a separation subsequent to an acidtreatment and a neutralization which comprises: executing a distillationin the presence of a stabilizing agent, said stabilizing agentconsisting solelysoian alkali metal salt of a volatile, non-polynierizingnon-o acid of which the anhydride is void 6,

2. In the production of light hydrocarbon oils from cracked distillates,the method of obtaining a separation subsequent .to an acid treatmentand a neutralization which comprises: executing a distillation in; thepresence'of a stabilizing. agent, saidstabilizing agent being an alkalimetal carbonate added in the ratio of about five or six pounds perbarrel of oil treated.

3. In the production of light hydrocarbbn oils from crackeddistill'ates, the method of obtaining a separationv subsequent 'to anacid treatment" anda neutralization which comprises: executing ad1st1llat1on 1n the preszu ga v ence of a non-polymerizing alkalinestabiliz ing agent in a subdivided state.-

4. In the production of light oils from cracked distillates, the methodof obtaining a separation subsequent to an acid treatment andaneutralization which comprises: executing a-distillation in the presence of a stabilizing agent, said-stabilizing agent consisting solely ofan alkali metal car-j bonate.

In testimony whereof, I have hereunto set hydrocarbon my hand at Los'Angeles, California, this.

3rd day of February, 1927. FRANK AXTELL.

